Ultra sensitive probes for detecting biomarkers

Abstract

The present disclosure provides compositions with ultra sensitivity for detecting a biomarker and the method of use thereof. In one embodiment, the composition comprises (1) a capture probe capable of binding to a biomarker and comprising a nucleic acid having a tail polynucleotide sequence; (2) a poly-oligonucleotide conjugate comprising a carrier conjugated with a plurality of oligonucleotides, wherein each oligonucleotide comprises a first region comprising multiple repeating polynucleotide sequences, wherein at least one of the plurality of oligonucleotides comprises a second region capable of directly or indirectly associating with the tail polynucleotide sequence; and (3) a plurality of label probes, wherein each label probe capable of directly or indirectly associating with the repeating polynucleotide sequence, wherein the capture probe, the poly-oligonucleotide conjugate and the plurality of label probes form a complex.

1 . A method of detecting a biomarker in a sample, said method comprising:
 (a) applying a capture probe to the sample, wherein the capture probe specifically binds to the biomarker and comprises a nucleic acid having a tail polynucleotide sequence;   (b) applying a poly-oligonucleotide conjugate to the sample, wherein the poly-oligonucleotide conjugate comprises a carrier conjugated with a plurality of oligonucleotides, wherein each oligonucleotide comprises a first region comprising multiple repeating polynucleotide sequences, wherein at least one of the plurality of oligonucleotides comprises a second region capable of directly or indirectly associating with the tail polynucleotide sequence, thereby associating the poly-oligonucleotide conjugate with the capture probe bound to the target biomarker in step (a);   (c) applying a plurality of label probes to the sample, wherein each label probe capable of directly or indirectly associating with the repeating polynucleotide sequence, thereby associating the plurality of label probes with the poly-oligonucleotide conjugate bound to the capture probe in step (b); and   (d) detecting the label probes associated with the poly-oligonucleotide conjugate in step (c).   
     
     
         2 . The method of  claim 1 , wherein the biomarker is a nucleic acid. 
     
     
         3 . The method of  claim 2 , wherein the nucleic acid is selected from the group consisting of a genomic DNA, a cDNA, a mRNA, a rRNA, a miRNA, a Lnc RNA and a siRNA. 
     
     
         4 . The method of  claim 1 , wherein the biomarker is a protein. 
     
     
         5 . The method of  claim 4 , wherein the capture probe comprises an antibody against the protein. 
     
     
         6 . The method of  claim 1 , wherein the tail polynucleotide sequence consists of 10-40 nucleotides. 
     
     
         7 . The method of  claim 1 , wherein the carrier is a polymer, a nanoparticle, a bead, a liposome or a micelle. 
     
     
         8 . The method of  claim 7 , wherein the polymer is selected from the group consisting of: polysaccharides such as dextrans and derivatized dextrans; vinyl polymers such as poly(acrylic acid), poly(acryl amides) and co-block polymers thereof; polyethylene glycol, polypropylene glycol and their derivatives; block co-polymers such as poly(ethylene oxide-co-propylene oxide); hyperbranched polymers such as PAMAM dendrimers; poly amino acids such as poly-lysine; proteins such as albumins and immunoglobulins; or a combination thereof. 
     
     
         9 . The method of  claim 1 , wherein the repeating polynucleotide sequence consists of 10-40 nucleotides. 
     
     
         10 . The method of  claim 1 , wherein the second region is capable of hybridizing to the tail polynucleotide sequence. 
     
     
         11 . The method of  claim 1 , wherein the second region is capable of associating with the tail polynucleotide sequence via a bridge probe. 
     
     
         12 . The method of  claim 1 , wherein the label probe has a sequence capable of hybridizing to the repeating polynucleotide sequence. 
     
     
         13 . The method of  claim 1 , wherein the label probe is capable of associating with the repeating polynucleotide sequence via a bridge probe. 
     
     
         14 . The method of  claim 1 , wherein the label probe comprises a detectable label. 
     
     
         15 . The method of  claim 14 , wherein the detectable label is a fluorophore, a horse radish peroxidase or an alkaline phosphatase. 
     
     
         16 . The method of  claim 1 , wherein the sample is a cell or tissue sample. 
     
     
         17 - 18 . (canceled)